One for the gas side, since electric gets most of the attention here.
Mechanical gas index meters have a fixed number of dials and they roll over to zero when they exhaust them. On a small commercial service that might happen once a decade, so nobody is watching for it. When it happens, the read difference goes sharply negative, and depending on how the billing system handles that you get either a wildly wrong consumption figure or a suppressed bill that quietly estimates for months.
What made this one hard to spot: the estimated bills that followed were plausible. They were in the right range for the season and the account. Nothing looked wrong on any individual statement. It only surfaced when I laid twenty-four cycles side by side and looked at the read sequence itself rather than the consumption figures.
Things I now check on any account with a mechanical gas meter.
The read sequence across the whole period, not the consumption. Look for a negative difference or an implausible jump.
The read type field on every cycle. A run of estimates is the signature.
Whether the number of dials on the meter is consistent with the annual volume. If the account burns close to a full meter cycle a year, rollover is a live risk rather than a theoretical one.
The rebill, when it comes, is usually large and usually arrives with no explanation at all.
Mechanical gas index meters have a fixed number of dials and they roll over to zero when they exhaust them. On a small commercial service that might happen once a decade, so nobody is watching for it. When it happens, the read difference goes sharply negative, and depending on how the billing system handles that you get either a wildly wrong consumption figure or a suppressed bill that quietly estimates for months.
What made this one hard to spot: the estimated bills that followed were plausible. They were in the right range for the season and the account. Nothing looked wrong on any individual statement. It only surfaced when I laid twenty-four cycles side by side and looked at the read sequence itself rather than the consumption figures.
Things I now check on any account with a mechanical gas meter.
The read sequence across the whole period, not the consumption. Look for a negative difference or an implausible jump.
The read type field on every cycle. A run of estimates is the signature.
Whether the number of dials on the meter is consistent with the annual volume. If the account burns close to a full meter cycle a year, rollover is a live risk rather than a theoretical one.
The rebill, when it comes, is usually large and usually arrives with no explanation at all.